Reversing cam drum for quick traverse winder and traveller for said reversing cam drum

ABSTRACT

A reversing cam drum for textile machines, particularly for quick traverse winders, the drum having a helical double groove, a central guide rail between the grooves, and including a traveller which traverses a thread guide and is guided within the double groove. The opposite threads of the double groove are interconnected by sinusoidal transition curves at the reversing points at each end of the drum.

United States Patent [191 May Dec. 17, 1974 [54] REVERSING CAM DRUM FOR QUICK 3,036,810 5/1962 Conrad et a1. 74/57 TR VERS WINDER AND TRAVELLER 3,048,054 8/1962 Helm 74/567 3,672,587 6/1972 Pierce 242/43 FOR SAID REVERSING CAM DRUM Inventor: Erhard Thaddaus May, Kempten,

Germany Assignee: Firma A. Ott, Kempten, Germany Filed: Aug. 15, 1973 Appl. N0.: 388,609

Related U.S. Application Data Continuation of Ser. No. 155,821, June 23, 1971, abandoned.

Foreign Application Priority Data June 26, 1970 Germany 2031562 U.S. Cl 74/57, 242/43, 74/567 Int. Cl. Fl6h 25/12 Field of Search 74/57, 567; 242/43 References Cited UNITED STATES PATENTS 8/1884 Ostrom 74/567 Primary Examiner-Benjamin W. Wyche Assistant Examiner-Wesley S. Ratliff, Jr.

Attorney, Agent, or FirmMelville, Strasser, Foster & Hoffman [57] ABSTRACT A reversing cam drum for textile machines, particularly for quick traverse winders, the drum having a helical double groove, a central guide rail between the grooves, and including a traveller which traverses a thread guide and is guided within the double groove. The opposite threads of the double groove are interconnected by sinusoidal transition curves at the reversing points at each end of the drum.

5 Claims, 5 Drawing Figures PATENTED m 1 W4 3'. 854,343

INVENTORS E l/ARD rx/Aaoh'z/s MA) 41504445, 577946552 #22575? (HOFFMAN PATENIED DEC] 7 I974 sum 3 or 5 INVENTORS Ee /4.60 n/Aoa'ws MA) BY Mar/14E, 57/645552, F0575? {HOFFMAN REVERSING CAM DRUM FOR QUICK TRAVERSE WINDER AND TRAVELLER FOR SAID REVERSING CAM DRUM This is a continuation of application Ser. No. 155,821, filed June 23, 1971, now abandoned.

This invention relates to a reversing cam drum for textile machines, especially for quick traverse winders, including a helical double groove, a central guide rail between the pair of grooves, and a traveller for traversing the thread guide and being guided within the double groove, wherein the opposite threads of the double groove are interconnected by transition curves at the reversing points at the end of the drum respectively.

By rotation of the said reversing cam drum the traveller being guided by the double groove will be oscillated between the ends of the reversing cam drum. Passing a transition curve which is provided at each of the pair of reversing points the traveller enters opposite threads of the double groove, thus being guided in opposed oscillating a traveller on a traversing cam drum is that on the one side the traveller is desired to be constructed with as great a length as possible that it might pass the crosspoints of intersecting opposite lefthanded thread curve and right-handed thread curve in a completely accurate way. On the other side the traveller is desired to be constructed as short as possible that it might pass the narrow transition curves at the reversing points where the said curves may form an acute angle theoretically, the traveller being guided along this path from a left-handed thread to a right-handed thread or vice versa without any interference as by jamming. In most reversing cam drums known in the art provision is made for a reversal at an angle as acute as possible in order that accumulation of threads at the reversal points of the cheeses might be prevented. In practice however reversal may be executed on an arcuate path having no strongly accentuated apex, the result of winding being satisfactory nevertheless.

There are however problems with regard to uncertainty of guidance of the traveller in the points of reversal, the said uncertainty increasing particularly in high speed processing, or with regard to unfavorable acceleration or deceleration strongly affecting driving mechanism or thread guide and causing heavy noise.

Proposal was made for extension of the central guide rail almost as far as the reversing point and for banking up the reversing region for preventing trouble when the traveller is passing the groove, particularly with reversing cam drums of the kind mentioned above. Guidance of the traveller at the reversing points would be better then, but detrimental acceleration or deceleration as well as noise would occur just as before. Moreover for banking up of the reversal regions the reversing cam drum has to be fabricated either from a wider diameter blank, which has to be turned down to a smaller diameter between the reversing points in order to have correctly shaped the reversing cam drum, i.e., high metal cutting expenditure of work, or by forming the reversal guidance surface upon an annular member, detachably positioned upon the reversing cam drum, i.e., two further sections of a reversing cam drum which have to be machined separately.

It is accordingly the object of the invention to provide a reversing cam drum for textile machines, especially for quick travers winders, of the kind mentioned above, in which the traveller is accurately guided at the reversing points even under high speed conditions, in which acceleration or deceleration conditions are substantially improved and which is simple in structure.

This is achieved in accordance with the present invention by designing the transition curves each as onehalf of a complete sine cycle. It is an improvement with regard to the prior art, where the transition curves were designed as a circular path, in that the sinusoidal trace of the transition curves in accordance with the present invention gives rise to much softer acceleration or deceleration of the moving bodies near the reversing points. In a circular path maximum forces of acceleration and deceleration will occur abruptly on leaving and entering the rectilinear groove and entering and leaving the circular transition path respectively, these noncontinuous acceleration or deceleration conditions possibly resulting in uncontrolable wabbling of the traveller, in increased abrasion and in increased noise, whereas nothing of the kind will occur with a sinusoidal design of the transition curves. With the said sinusoidal design the forces of acceleration or deceleration will gradually increase from zero, when the traveller is leaving the rectilinear portion of the double groove and is entering the transition curve, up to its maximum value appearing at the top of the transition curve, i.e., the sine curve. After this the forces mentioned above will disappear gradually. By continuous increasing or decreasing of the accelerating or decelerating forces the traveller will pass the reversing points at a substantially smoother mode, built up reversing surfaces being thus unnecessary. The reversing cam drum thus will show a relativly simple structure and its manufacture will be less expensive. Moreover abrasion in the reversion points and noise will be reduced. It is still an advantage of the reversing cam drum in accordance with the invention that the length of the sine curve may be made such that acute reversal of the thread in the cheeses may be obtained. With regard to improved guidance of the traveller in the reversing points and to acceleration or deceleration conditions a greater number of traverses may be allowed in comparision with the prior art.

According to further development of the invention it may be preferred to extend the central guide rail between the transition curves at the reversing points of the groove and to make provision of an arcuate enlargement at the inner face of the central guide rail opposed to the center of the reversing cam drum, the shape of the enlargement being defined by the path of final edges of the guiding surface coating with the said inner face and being provided at a longitudinal groove of traveller known in the art. In this way a particularly accurate guidance of the traveller at the reversing points is obtained, for the traveller will be guided not only at its periphery by means of the outer limiting surface of the double groove or of the transition curve but also by means of the inner surface of the central guide rail engaging the final edges of the longitudinal groove provided within the traveller. In this manner the traveller will be engaged at three points at least, preventing any wabbling.

The above and further objects and novel features of the invention will more fully appear from the following description in connection with the accompanying drawings which are for the purpose of illustration only and are not intended as a definition of the limits of the invention.

IN THE DRAWINGS FIG. 1 is a partial view in elevation and partly in longitudinal section of the reversing cam drum in accor dance with the invention.

FIG. 2 is a partial view of the development of the double groove in one of the pair of reversing points.

FIG. 3 is a view as in FIG. 2 with further specification for the design of the sine curce.

FIG. 4 is a underside plan view of a traveller at a twofold scale, seen from IV of FIG. 5.

FIG. 5 is a longitudinal section of the traveller along the line VV of P16. 4.

In the drawings 1 designates the reversing cam drum with its helical double groove 2,2. Section 2 of the double groove on the periphery of the reversing cam drum forms a left-handed thread and section 2 of the said double groove forms a right-handed thread. Between the pair of grooves forming the double groove a central guide rail 3 is provided that is interrupted by an opposite groove respectively. At the ends la of the reversing cam drum 1 the reversing points are provided where the left-handed thread section 2 of the double groove is passed to the right-handed thread section 2' by means of a pair of transition curves 4,4 respectively. Within the pair of grooves of the said double groove a pair of skids 5 of a traveller is moved respectively, the traveller being designated by reference number 6 in FIGS. 4 and 5. The traveller 6 is given a to-andfro movement in the direction of arrow A (FIG. 1) by rotating reversing cam drum 1; in this way the traveller is traversing a thread guide (not shown).

According to the invention transition curves 4, 4' are designed each as a sine curve. Because it is not so important what a path the skids 5 of the traveller 6 will take, it being indispensable on the other hand, that the center of the pivot 7 of the traveller 6, the said pivot being connected to a thread guide, will move along a desired path, it is desirable that center line M which is provided between the pair of outer limiting surfaces 8, 8 of transition curves 4, 4' has the shape of a sine curve at the reversion points. The center of pivot 7 is moving along the trace of center line M. The pair of limiting surfaces 8, 8 may be called an envelope of center line M.

In the embodiment shown the double groove 2, 2' extends under a gradient angle S of about 30. With this embodiment it is desirable to extend transition curves 4, 4 as far as about 1 10 or 120 on the arc of rotation of drum 1, this are being 1 12 in the embodiment shown. Thus the sinusoidal shape of center line M is beginning at the pair of points V. FIG. 3 demonstrates in which way a sinusoidal path might be designed as derived from center line M extending rectilinear over considerable portion of its length and passing to a sinusoidal shape at points V.

As desired central guide rail 3 is also provided within the transition curces 4,4 at the reversing points of double groove 2,2. The skids 5 of traveller 6 should be made as long as possible, on the other hand the said skids should be prevented from interferring with the groove at the reversal points; thus provision is made for an arcuated enlargement 10 at the inner face 9 of the central guide rail 3 positioned at the reversing points and opposed to the center of drum 1. The shape of enlargement 10 is defined by the path of the final edges 11 of guiding surface 12, this surface coacting with the inner face 9 and being provided at a longitudinal groove 13 known in the art. In this way the skids of the traveller are engaging the central guide rail 3 at three points B at least in the region of the reversing points, thus assuring completely accurate guidance of the traveller. Further engagement occurs between outer limiting surfaces 8, of transition curves 4,4 on periphery surfaces 14 of skids 5, thus assuring further guidance at the reversing points and in the rest of the double groove and ensuring less abrasion at the reversing points as well.

Enlargement 10 in central guide rail 3 ensures traveller 6, and particularly skids 5 of traveller 6 to be shaped particularly longs. In carrying out the invention the extension L of the skids 5 of traveller 6, i.e., the length of the inner surface 12 limiting longitudinal groove 13 should be about twice the distance between the outer limiting surfaces 8,8 of double groove 2,2.

Advantageously periphery surfaces 14 of skids 5 of travellers 6 coacting with outer limiting surfaces 8,8 of double groove 2,2 are designed as an arc of a circle with its radius R corresponding roughly to the radius R of outer limiting surface 8 of outer transition curve 4 at the reversing point; in this way traveller 6 will pass the said reversing points with as little interference as possible.

What is claimed is:

1. A reversing cam drum for textile machines, especially for quick traversing winders, including a pair of helical grooves having opposite hand threads, outer limiting surfaces and reversing points at the ends of drum claimed in claim 1, drum respectively, a central guide rail between the pair of grooves, and a traversing traveller guided within said pair of grooves, said opposite hand threads of said pair of grooves being interconnected by transition curves at said reversing points, wherein said transition curves each define one-half of a complete sine cycle, wherein said outer limiting surfaces comprise a pair of lateral surfaces defining limiting envelopes of the path of said traveller whereby a point of said traveller moves through the said cycle at each transition curve, and wherein said central guide rail is uninterrupted within said transition curve.

2. The reversing cam drum claimed in claim I, wherein said transition curves extend over an arc of rotation of said drum of from about to about and wherein said pair of helical grooves has a gradient angle of about 30.

3. A reversing cam drum for textile machines, especially for quick traversing winders, in combination with a traversing traveller, said cam drum including a pair of helical grooves having opposite hand threads. outer limiting surfaces and reversing points at the ends of the drum respectively, and a central guide rail between the pair of grooves, said traveller being guided within said pair of grooves and having skids with peripheral surfaces and guiding surfaces with final edges, said guiding surfaces defining a longitudinal groove therebetween, said longitudinal groove engaging said central guide rail, said opposite hand threads of said pair of grooves being interconnected by transition curves at said reversing points, each said transition curve defining onehalf of a complete sine cycle wherein said outer limiting 4. The combination claimed in claim 3, wherein said peripheral surfaces of said skids of said traveller coacting with said lateral surfaces have an arcuate configuration with a radius approximately corresponding to the radius of the lateral surface of an outer transition curve at said reversing point.

5. The combination claimed in claim 3, wherein the length of said guiding surfaces is about twice the distance between said lateral surfaces. 

1. A reversing cam drum for textile machines, especially for quick traversing winders, including a pair of helical grooves having opposite hand threads, outer limiting surfaces and reversing points at the ends of drum claimed in claim 1, drum respectively, a central guide rail between the pair of grooves, and a traversing traveller guided within said pair of grooves, said opposite hand threads of said pair of grooves being interconnected by transition curves at said reversing points, wherein said transition curves each define one-half of a complete sine cycle, wherein said outer limiting surfaces comprise a pair of lateral surfaces defining limiting envelopes of the path of said traveller whereby a point of said traveller moves through the said cycle at each transition curve, and wherein said central guide rail is uninterrupted within said transition curve.
 2. The reversing cam drum claimed in claim 1, wherein said transition curves extend over an arc of rotation of said drum of from about 110* to about 120*, and wherein said pair of helical grooves has a gradient angle of about 30*.
 3. A reversing cam drum for textile machines, especially for quick traversing winders, in combination with a traversing traveller, said cam drum including a pair of helical grooves having opposite hand threads, outer limiting surfaces and reversing points at the ends of the drum respectively, and a central guide rail between the pair of grooves, said traveller being guided within said pair of grooves and having skids with peripheral surfaces and guiding surfaces with final edges, said guiding surfaces defining a longitudinal groove therebetween, said longitudinal groove engaging said central guide rail, said opposite hand threads of said pair of grooves being interconnected by transition curves at said reversing points, each said transition curve defining one-half of a complete sine cycle wherein said outer limiting surfaces comprise a pair of lateral surfaces defining limiting envelopes of the path of said traveller whereby a point of said traveller moves through the said cycle at each transition curve, and wherein said central guide rail is uninterrupted within said transition curve and is provided with an arcuate enlargement at the inner face thereof opposed to the center of said drum, the configuration of said enlargement being defined by the path of said final edge of said guiding surface of the traveller in engagement therewith.
 4. The combination claimed in claim 3, wherein said peripheral surfaces of said skids of said traveller coacting with said lateral surfaces have an arcuate configuration with a radius approximately corresponding to the radius of the lateral surface of an outer transition curve at said reversing point.
 5. The combination claimed in claim 3, wherein the length of said guiding surfaces is about twice the distance between sAid lateral surfaces. 